1. Field of Disclosed Subject Matter
This disclosure relates to systems and methods for employing a unique optical roll scanning technique to identify surface defects, and particularly repetitive surface defects, for rolls usable in image production devices.
2. Related Art
Currently, certain roll components employed by image forming devices, including and particularly fuser rolls, experience defects related to, and potentially introduced by, among other things, flow coating processes by which the surfaces of the rolls are formed for use in image forming devices. Commonly, the introduced defects, manifested as repetitive defects of a frequency related to the finishing process, are referred to, among other things, as “barber pole” defects. The barber pole effect manifests itself often by appearing as stripes on the rolls, including the fuser rolls. The stripes are often presented at a same frequency as a pitch of the flow coating process by which the surface coatings of the affected rolls were formed. The presence of these stripes results in a reduction in image quality for images formed, fixed or otherwise processed on image receiving media substrates through contact with the barber poled rolls. These defects are often most discernible as they are printed out as gloss defects on dark solids.
The particular nature of the defect, while clearly discernible, and the root cause of the defect, have proven, over time difficult to isolate and, therefore, to specifically address in, for example, some modification of the finishing and/or flow coating process. As a result, a limitedly effective technique for determining whether a batch of finished rolls is acceptable for sale or other release for field use has been developed that involves selecting random samples from individual batches of finished rolls. These random samples are then tested to determine whether a level of any barber poling that exists is below an established threshold that represents an acceptable level for the entire batch of finished rolls. Metrics (established thresholds) for acceptable levels of barber poling on prints have been developed and are applied to the sampling process.
Those of skill in the art recognize that certain shortfalls exist in the above-described sampling methods of testing leading to approval of entire batches of finished rolls. Any batch, it is recognized, may include individual rolls that may include levels of barber poling that lie outside a range of what may be considered to be acceptable, which may be detected in the sampling process leading to customer dissatisfaction when employing those errant rolls. Currently, there is no effective method for direct roll measurement of defect levels, including barber pole levels, on each roll prior to release for use. All attempts to address these shortfalls to date, including the use of such techniques as laser and perth trace measurements, have failed to produce acceptable results even and to any extent that they could even have been effectively and/or reasonably implemented.
The state of the art, therefore, remains a technique in which only samples from each batch of produced rolls are print tested. If the prints from the samples of the rolls from each batch are below developed specification limits for barber pole defects or effects on produced prints, the entire batch is then deemed acceptable and released for sale or other field use. FIG. 1 illustrates a flowchart of the conventional, and generally currently-undertaken, process for sample roll testing and verification prior to release of a batch of rolls, from which the samples were selected, for use. As shown in FIG. 1, the conventional process commences at Step S1000 and proceeds to Step S1100.
In Step S1100, a batch of surface prepared rolls is completed. Operation of the conventional process proceeds to Step S1200.
In Step S1200, samples are selected at random from the batch of surface prepared (finished) rolls and the samples are sent for testing. Operation of the conventional process proceeds to Step S1300.
In Step S1300, machine time is scheduled for undertaking the samples testing. Operation of the conventional process proceeds to Step S1400.
In Step S1400, the selected sample rolls, and potentially a plurality of control rolls, are print tested. Operation of the conventional process proceeds to Step S1500.
In Step S1500, prints developed in the print testing step are sent to, and scanned by, a group that may analyze test patterns, such as an Image Quality Media Lab (IQML). Operation of the conventional process proceeds to Step S1600.
In Step S1600, quality control engineering personnel interpret the print scans and communicate the results of their interpretation (analysis) to manufacturing and distribution personnel. Operation of the conventional process proceeds to Step S1700.
In Step S1700, only after successful testing of the samples selected from the finished batch of rolls is complete is the finished batch of rolls released for sale and/or for other field use by the manufacturing or distribution personnel. Operation of the conventional process proceeds to Step S1800, where operation of the conventional process ceases.
The above-described conventional process is an expensive and time-consuming process. Machine time is expensive and adds the risk of machine variation to the analytic process. The time and expense of print testing rolls has limited the amount of testing aimed at understanding the root cause of, and critical parameters that drive, the barber pole effect/defect. Additionally, the sample-focused process may not be effective in detecting all incidents of barber poling defects in a particular batch of finished rolls, leading to potential customer dissatisfaction based on the effect on image quality produced by an out-of-specification finished roll that is not detected by the conventional sampling process.